Large PLA print lifting bed off of magnetic sheet

So I am trying to print some prints that take up most of the print bed and am having some problems with the build plate lifting off of the magnetic sheet.

It actually looks like it is pulling the magnetic sheet off the bed which can’t be good either.

This warping causes terrible top layer artifacts and dimensional problems where the bed is lifting, as shown below.

Does anyone have any tips on how to mitigate the chance of this happening?

That’s wild, is that the stock bed? I have a feeling Bambu would just come back with don’t print parts like that, the bed isn’t designed for those kinds of forces.

I’m a big fan of the Layerlock/Matterhackers textured PEI bed. To me it has a much stronger attraction to the bed than the stock plate. There is a noticeable difference in force when installing the two plates.

When I do large prints like that I just use a little bit of kapton tape on the left right and front of the bed to secure it to its base. A little carry over from the old ender days as even the strongest magnets won’t be able to hold in place especially at the edges of the bed.

This would be a temporary fix while you get the magnet replaced from Bambu. However carry on doing that once you get the new bed as the magnetic adhesion some times gets overpowered by the warping forces in the printed item, when printing large parts like this with sharp corners.

The 2nd pic looks like the magnetic sheet itself (not just the steel build sheet) is lifting off the heat bed. Definitely a support ticket worthy issue.

Yes, using the cool plate. I had to up the temp 5 or 10 degrees to get good enough adhesion where it wasn’t coming off the plate, but now the warping force is just overcoming the magnetic force between the build plate and the bed lol.

That’s pretty terrible that a 3D print would peel up the magnetic sheet for the bed. I 2nd the two previous posts, definitely file a ticket since the magnetic itself seems to be lifting from the bed surface. And try out the kapton tape that @ioannis recommended.

Cannot say this would work and it may not be a desirable outcome depending on the use, etc but something I tried awhile back and still practice now is when printing large prints with Taulman’s alloy 910 nylon filament is to create alot of pockets on the surface that touches the bed (remove material and leave pockets of empty space behind). This eliminates alot of direct contact with the bed. With practice you can tell where you can remove material and leave enough behind to prevent warping in odd areas. After looking closer I realized my suggestion may not be idea at all if it’s the visible surface in the end. I typically split alot of parts in half and bolt them together afterwards - hiding the bed surface.

What extruder temperature are you printing at? What bed temp are you printing at?

Warping occurs because the layers further from the build plate cool faster than the layers closer to the build plate. As they cool, they shrink more that the warmer lower layers, and this causes the print to “potato chip”, it curves upwards at the bottom edges to relieve the inward pulling stress at the top. A hotter build chamber temp will often help. But with PLA you need to be careful the extruder doesn’t plug because the filament is getting too hot before it gets to the nozzle.

Where possible I try to put stress-relief “risers” in my models, thin vertical notches. This reduces the amount of “connected” filament which reduces the region that can pull in/up on the outer edges of the print as it cools, which reduces the stress, which reduces the warping. They can be easy to hide in the Infill and can be a very effective solution, albeit at the cost of some strength (maybe a lot depending on what you’re printing).

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We did not have a single acceptable full plate print from PLA/Cool Plate whereas we have very few problems with the textured PEI.

I’m printing at 220C using black inland PLA+. I’ve run flow rate, pressure advance, and max flowrate calibration and limited my volumetric print speed to 23 mm3/s (which I don’t even think this print is hitting.)

My bed temp is 40C, bumped up from the stock bed temp (which I think is 35C?) This may be why people have better luck with the textured PEI sheet, that needs a higher temp for adhesion and therefore doesn’t let the part cool down as fast. I have one at home that I’ll bring in to try (the problem is on the work printer which is especially frustrating.)

As for changing the model, I’ve thought about it but really don’t want to start adding tons of reliefs for printing. If necessary I guess I’ll have to but I’m already designing most parts to prevent overhangs and other FDM friendly features but things can get unnecessarily complicated pretty quickly. What do you (or does anyone else) think about possibly just removing all bottom layers? For some parts such as this one we don’t really care about the bottom surface, just the top with the markers. I’m just worried that printing infill directly on the plate won’t have enough adhesion (or this might not even be a good idea in the first place.)

Also, an update on some changes. I changed the infill from grid to gyroid which made an improvement, but still definitely not the quality we’re looking for. This definitely reinforces the concept that long straight lines are not good as they when expand and contract they transmit that movement to the overall part rather than staying sort of contained within the infill. On this print and the previous we also see some of the infill showing through on the top layer even with 3 top layers as well.

Also, I’ve attached a pic of the first layer to show that there’s no bed adhesion issues (ignore the greasy finger marks.)

I print PLA with a 55 or 60º bed temp. A hotter bed will help with your problem. The printer may complain that 60º is above the filament’s vitrification temp, but it hasn’t been an issue for me. Also, I run the chamber fan at 70% and I leave the door closed.

I’ve been pretty happy with the Inland filament. They sell it at a local MicroCenter so it’s something that’s available within an hour or so of needing it. ASA and PETG work great. Both are more challenging to print than PLA.

What do you (or does anyone else) think about possibly just removing all bottom layers?

I haven’t tried it with my X1C, but I had printed a lightweight small radio control flying wing with my older printer. The way I made it light was by setting top and bottom surface count to 0, and printing a 10% infill. Ended up with infill in the shape of the wing. Wrapped some lightweight covering material around that (think “saran wrap”) and viola!

Setting bottom layers to zero ought to work fine. Just set your first layer to slooooow.

This may warp more, though. The bottom will not resist tension from the top as well if there’s no solid layers on the bottom. But… try flipping the part over if you can, so that you’re not printing a top layer. Eliminating that top layer will eliminate a lot of the stress that causes the bowing.

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This is rather than expected.

Regarding the solution, the most reliable and permanent is to replace the magnetic plate and sticker. It is easy, but you must contact Bambu as the sticker is not listed in the store items. If the components are “new”, you may be entitled to a replacement.
While waiting, I will avoid large prints and use tape to overcome the issue.

Regarding the why, it can be many things or a combination.
I already printed using the “complete” bed (i.e. without surpassing the limits imposed in the slicer) with PLA and cold plate without any issue.

Did you change the g-code for using the entire area?
How long do you have your printer?
Before starting the print, were both in good condition? Despite being consumables, they tend to last.

Are you using glue on the bed sheet? If so, it would be expected that the print lifts off or wrap in the corners, but never to drag the bed plate with it. This seems a firm adhesion.
Did you test another PLA filament?
Sorry for the many questions, but this is strange.

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The inland filament has been great to me so far too, I’ve tried PLA, PETG, and ASA and they all work fine on multiple enders and my bambu X1C at home. I’m going to try printing this model with my home printer and the textured PEI plate to see if that changes anything.

On the topic of printing upside down- the lettering doesn’t seem to come out as clearly when printing text flush face down versus printing a couple of layers on top. It also creates a lot more waste due to more filament changes. I definitely want to try that process for inlaying text for other cosmetic stuff but for these fixtures the quicker way seems to be better.

Printing with no top or bottom layers is a pretty cool tip though- I’ll try to use that for weight savings some time.

So this print is not taking up 100% of printable space- just most of the build plate. I’d estimate that there’s about half an inch to an inch of empty bed all around the model (which might be worse than just printing on the whole bed?)

We’ve only had the printer for about a month or two. Everything seems to be fine, this printer has some more z artifacts that my home printer doesn’t but that seems to be a common issue. Funnily enough, the green bambu PLA that came with the printer seems to barely work (poor bed adhesion), while all other filaments I’ve tried work fine.

Most prints I use the glue to stick to aid removal but this model was pulling up off of the build plate so I stopped using glue on this one.

By the way, here are the settings I’m going to be printing with (for future reference.) The PLA profile is calibrated with flow rate, pressure advance, and max volumetric flow rate, and the printing settings are the standard orcaslicer 0.2mm layer height profile, just changing the infill to gyroid.



I also just washed the textured build sheet with dish soap and water so there shouldn’t be any layer adhesion issues.

This is a part of the sliced model that is a little smaller than the last one I printed so let’s see what happens in about 6 or 7 hours lol.

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Turn off the part cooling fan and the aux fan.
Disable them for the entire print.

-Uman

I’ve been having the same problem with a large paht-cf print. I printed some “Bed Clamps (low profile) for Bambu Lab X1/P1P” (@BlindMaker_275069) that can be found on printables.

They solved the problem for me.

Ok, so some interesting results here. I printed this on my home printer using the textured PEI sheet.

First of all, printing on the textured PEI worked a lot better. I suspect this is not due to the actual bed but the increased bed temp.

There are still some artifacts making this print not have the quality as expected though. I suspect that at least two of the corners lifted slightly (pics below.)


The first picture shows a rough texture on the top layer, and the second picture shows that the .644 text is slightly thicker than the surrounding labels. It looks to me like the first layer of that text was squished compared to subsequent layers.

One last thing (that might make this test invalid in the first place…) is that I have some underextrusion(?) going on as shown below:

The volumetric flow rate of 23mm3/s might just be too high for this filament. It also dawned on me that this was calculated based on the printer we use at work, not the one I printed this model on for this test. What is strange to me is that from the printed model I’d expect to see some sort of difference in speed from the layers printed where the hole feature is, but the slicer shows everything moving at the same speed:

So if the print lift of the plate with glue, I would continue using glue to avoid the sticker detachment and bed sheet bending.
For the corner wrapping, you can try heating the bed to a higher temperature, doing a minor print to check if the bed is levelled, trying different cooling settings (e.g. instead of 4 layers without cooling, try a smaller number), using brim, raft, tune the first layer thickness and speed, …

Regarding your print at home, the issues are, in my opinion, solvable by calibrating the filament or by the fastest solution (which I usually do), reducing the print speed at the outer wall and top surface.
Is the INLAND filament? 23 mm3/s is high. This is the typical value for the market’s highest-speed PLA filaments (e.g. BL, polyterra). I never used INLAND filament, and neither found a datasheet, so maybe it is correct. If both printers are the same model and use the same nozzle, I do not expect changes in the filament max flow rate.

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